Diesters of terminally unsaturated monocarboxylic acids and halophenoxymethyl, alkane diols



United States Patent 0 3,225,002 DIESTERS 0F TERMINALLY UNSATURATEDMONOCARBOXYLIC ACIDS AND HALO- PHENOXYMETHYL, ALKANE DIOLS Marco Wismerand Roger M. Christensen, Gibsonia, Pa.,

assignors to Pittsburgh Plate Glass Company, Pittsburgh, Pin, acorporation of Pennsylvania No Drawing. Filed Feb. 17, 1961, Ser. No.89,919 12 Claims. (Cl. 260-47) This invention relates to novel chlorinecontaining diesters, and to the preparation thereof, and pertains morespecifically to the reaction of halogenated diols with unsaturatedmonocarboxylic acids, to produce novel halogen containing d-iesterswhich homopolymerize or copolymerize with other monomeric materials togive useful polymers.

It is known that the CH C linkage in unsaturated monocarboxylic acidssuch as acrylic acid or methacrylic acid is quite reactive, and the freeacids as Well as the esters thereof are frequently utilized as onecomponent of polymerizable mixtures. It is also known that the presenceof halogen in a polymer appears to enhance to a considerable extent theframe retardant properties thereof.

The interest in flame retardant acrylates is evidenced by the work ofSurnrel et 211., as reported in the Journal of the American ChemicalSociety, volume 81, 1959, towards producing halogenated phenylmethacrylates. Also, US. Patent 2,338,683 discloses esters ofhalogenated aryloxysubstituted lower alcohols with certain unsaturatedaliphatic monocarboxylic acids. In each of these instances the estershave the limitation of being monofunctional.

It has now been discovered that it is possible to combine in a singledifunctional monomer the reactive properties of the unsaturatedmonocarboxylic acid, and the fire retardant properties of chlorine,bromine or fluorine. This is accomplished in the present invention byreacting a halogenated diol, such as 2-pentachlorophenoxymethyl- Z-ethyl1,3-propanediol, with an unsaturated monocarboxylic acid. In thisprocess a diester is formed by the reaction between the alcohol radicalsand the hydroxyl radical of the carboxylic acid group with theelimination of Water. The reaction is believed to proceed substantiallyas follows, wherein 2'pentachlorophenoxymethyl-2-ethyl 1,3-propanedi0land methacrylic acid are used for illustrative purposes:

Alternative methods of preparation of said diester include the esterinterchange reaction wherein the diol is reacted with a low-boilingester or" the monoethylenically unsaturated carboxylic acid in thepresence of a catalyst, and the acid chloride-diol reaction wherein amonoethylenically unsaturated carboxylic acid chloride is reacted withthe diol, preferably in the presence of an acid acceptor such aspyridine.

The novel compounds prepared by reactions of the type describedhereinabove possess the following structure:

R is a hydrogen radical or an alkyl radical containing 1 to 10 carbonatoms, with the limitation that when R is 0 Rs odt :=on

then R can be only hydrogen; R is a member of the class consisting ofhalogen radicals, hydrogen and alkyl radicals (such as methyl, ethyl,propyl, butyl, amyl, octyl, dodecyl and the like); and Ar-is amononuclear aromatic hydrocarbon radical containing from 1 to 5 halogensubstituents selected from the class consisting of chlorine bromine andfluorine,

Compounds of this type polymerize in the presence of catalysts, such asperoxygen compounds, to form hard, clear homopolymers, or can bepolymerized with other monomers, such as methyl methacrylate and thelike, to give interpolymers with many useful properties, the most;important being fire retardation. In addition to fire retardation,homopolymers and interpolymer castings made from the herein describeddifunctional monomers have vastly improved hardness and high-temperatureheat distortion properties over similar castings prepared frompreviously known monofunctional monomers.

Suitable unsaturated monocarboxylic acids for the above describedreaction include acrylic acid, methacrylic acid, ethacrylic acid,alpha-chloroacrylic acid, alphabromoacrylic acid, alpha-lluoroacrylicacid, and similar materials.

Some diols, such as Z-pentachlorophenoxymethyl-2- ethyl 1,3-propanedioland the like, used as reactants in this invention have been known foronly relatively short periods of time. Copending application Serial No.844-,- 180, filed October 5, 1959, discloses the preparation of suchdiols as Z-pentachlorophenoxyinethyl-Z-ethyl 1,3- propanediol by thereaction of trimethylolpropane and hexachlorobenzene in the presence ofa hydrogen chloride acceptor, such as sodium hydroxide, sodium carbonateand the like. The reaction therein disclosed involves admixing thereactants in a suitable solvent such as dimethoxymethane,dimethoxyethane and the like, with best results obtained at elevatedtemperatures. The salt formed by the reaction is removed by filtrationor other means, after which the solvent is removed by vacuumdistillation.

Other diols, such as l-pentachlorophenoxy 2,3-propanediol,l-pentabromophenoxy 2,3-propanediol, l-pentafiuorophenoxy2,3-propanediol, l-monochlorophenoxy 2,3-propanediol, l-dichlorophcnoxy2,3-propanediol, 1- trichlorophenoxy 2,3-propanediol, l-monobromophenoxy2,3-propanediol and the like can be used as reactants in this invention.Copending application Serial No. 811,003, filed May 5, 1959, now PatentNo. 3,004,073, discloses a new method of preparation of such diols asl-pentachlorophenoxy 2,3-propanediol by the hydrolysis of pentachlorophenyl glycidyl ether in the presence of a strong acid catalyst such assulfuric acid.

The halogentaed diols obtained by the above procedures are generallysolid materials. It is accordingly desirable that the esterificationreaction be carried out in a solvent utilized in an amount such as toprovide a readily stirrable reaction mixture. Suitable solvents includebenzene, toluene, xylene and the like. An acid catalyst such asbenzenesulfonic acid, p-toluenesulfonic acid, or mineral acids such asphosphoric acid, sulfuric acid, and the like, is desirable to promotethe esterification reaction. A reaction temperature of about 60 C. to110 C. is desired to minimize the polymerization of the unsaturatedmonocarboxylic acid. It is also desirable that a polymerizationinhibitor be included to preclude the polymerization of the unsaturatedmonocarboxylic acid. Such inhibitors for this purpose includehydroquinone, picric acid, dinitrophenol, p-cyclohexyl phenol,catechols, and the like.

As indicated hereinabove, two moles of the unsaturated monocarboxylicacid are required stoichiometrically to react with one mole of the diol.Generally a slight exces of the diol is used to insure completeesterification of the acid, although other ratios may also be employed.

As the reaction proceeds water is formed. The water is preferablyremoved by azeotropic distillation with benzene, and subsequent phaseseparation, with the benzene being returned to the reaction vessel.Removal of the water promotes faster reaction since the esterificationreaction is reversible. The reaction tempertaure is determined by theazeotropic boiling point of the solvent and Water. When the reaction iscomplete, which can be determined by the amount of Water removed, thebenzene is separated from the product by vacuum distillation.

The monomeric compounds obtained by the process described hereinabovepolymerize readily when heated in the presence of a small amount of aperoxygen catalyst such as 'benzoyl peroxide, cumene hydroperoxide,lauroyl peroxide, acetayl peroxide, or the like, to give homopolymerswhich are hard and strong, and which, as indicated hercinabove, areunusually flame retardant. In a similar manner, these monomers can beadmixed with other monomeric materials in the presence of a catalyst andheated to give interpolymers which also possess many useful propertiesincluding the excellent flame retardation of the homopolymers.

The following examples illustrate in detail the preparation of novelmonomers by the reaction of halogenated diols with unsaturatedmonocarboxylic acids, and the polymerization of such monomers to formhomopolymers and interpolymers. The examples are not intended to limitthe invention, however, for there are, of course, numerous possiblevariations and modifications.

Example I The methacrylate diester of Z-pentachlorophenoxymethyl-Z-ethyl1,3-propanediol was prepared utilizing the following materials in theamounts set forth:

Grams 2-pentachlorophenoxymethyl-Z-ethyl 1,3-propanediol (OH value293.7) 1 195.0 Methacrylic acid 2 87.5 Benzenesulfonic acid 10.0 Picricacid 0.44 Benzene 176.0

1 1.02 equivalents. 2 1.00 equivalent.

These materials were admixed in a glass reaction vessel. The benzene wasadded during the heating of the other materials to promotesolubilization and to control reflux temperature. At 60 C. a clear,light yellow solution was obtained. After 3 /2 hours refluxing at 91 C.,the reaction was complete.

The resulting solution was washed with aqueous NaCl and NaHCO andfiltered giving a clear yellow filtrate. After adding 0.565 gram ofhydroquinone, the benzene was vacuum distilled (0-5 mm. of Hg) at a pottemperature of C. A dark yellow, syrupy fluid was obtained.

This fluid was recrystallized from a n-heptane solvent, yielding a whiteprecipitate. After several recrystallizations from an acetone solution,white crystals were obtained and subsequently recovered by filtration.

The crystals obtained were analyzed by infra-red and microanalysis. Theinfra-red analysis indicated the presence of the carbonyl group and thedouble bond. The microanalysis of the resultant crystals was comparedwith the theoretical composition of the desired diester.

Percent Percent Percent carbon hydrogen chlorine Experimental values 46.32 4. 21 34. 21 Theoretical values 46. 31 4. 05 34. 2O

The saponification number of the resulting crystals was 216.0 ascompared with the theoretical value of 216.6 for the diester. A meltingpoint of 75 C.-75.5 C. was obtained.

Example II The methacrylate diester of2-pentachlorophenoxymethyl-2-methyl 1,3-propanediol was preparedutilizing the following materials in the amounts set forth:

Grams 2 pentachlorophenoxymethyl 2 methyl 1,3-propanediol (OH value304.1) 72.9 Methacrylic acid 321.7 Benzenesulfonic acid 3.8 p-Cyclohexylphenol 0.78

0.305 equivalent. 2 0.387 equivalent.

Pcrcent Percent Percent carbon hydrogen chlorine Experimental values 45.3. 82 34. 94 Theoretical values 45. 21 3. 77 35. 15

Acrylic acid, when substituted for the methacrylic acid used in thisexample, reacts similarly, yielding the acrylate diester of2-pentachlorophenoxymethyl-2-methyl 1,3- propanediol.

Example III The acrylate diester of 2-pentachlorophenoxymethyl-Z- ethyl1,3-propanediol was prepared utilizing the following materials in theamounts set forth:

Grams 2 pentachlorophenoxym'ethyl 2 ethyl 1,3-propanediol (OH value29.0) 198.0 Acrylic acid 2 82.8 Benzenesulfonic acid 10.0 p-Cyclohexylphenol 3.0 Benzene 176.0

1 1.02 equivalents.

1.00 equivalent.

These materials were admixed in a glass reaction ves sel. The reactionprocedure was similar to previous examples. The reaction product wasseparated from the benzene solvent by vacuum distillation. The crudeproduct was solubilized with ether and then washed several times withNaHCO solution and with water. The ether solution was dried over Na SOthen the ether was removed by vacuum distillation. A light yellowviscous product was obtained. The saponification number of this productwas 209.9 as compared with a theoretical value of 227 for the desireddiester.

Example IV A casting of a m'ethacrylate diester, similar to thatprepared in Example I was made by adding 28.46 grams of moltenmethacrylate diester to a glass container containing 431 milligrams ofbenzoyl peroxide dissolved in 1.77 grams of methyl methacrylate. Thissolution was poured into a cell and oven cured. After 2 /2 hours at 170F., the material had gelled. Over an eight-hour period the temperaturewas gradually raised to 325 F. The temperature was held at 325 F. fortwo additional hours. The resultant casting was clear with a lightyellow tint.

The casting was found to be very flame resistant and qualified asself-extinguishing when tested according to ASTM Test Method D635-44.The casting was held in a flame for 30 seconds and then removed from theflame. The casting ceased to produce a flame immediately after removal,which is very superior according to ASTM specifications which consider aself-extinguishing period of 60 seconds as flame retardant.

Example V The methacrylat'e ester of l-pentachlorophenoxy 2,3-propanediol was prepared utilizing the following materials in theamounts set forth:

Grams l-pentachlorophenoxy 2,3-propanedi-ol 177.5 Methacrylic acid 287.3 Benzenesulfonic acid 10.0 Dinitrophenol 2.0

1 1.02 equivalents. 9 1.00 equivalent.

These materials were admixed and heated in a glass reaction vessel.During the heating of these materials 200 milliliters of benzene wereadded to promote solubilization and to control reflux temperature. At 60C. a dark, yellow solution was obtained. The solution was heated to 84C., at which temperature it began to reflux. The reaction was continuedfor about 23 hours at which time a temperature of 127 C. had beenreached and a total of 16.6 milliliters of water had been collected.

The resulting solution was diluted with benzene and washed with 5percent aqueous NaOH to remove any unreacted acid and the dinitrophenolinhibitor. The solution was then washed with water and filtered. Fivehundred thirty (530) milligrams of hydr-oquinone were added and thebenzene was removed by vacuum distillation.

The resulting monomer polymerized in the presence of a peroxide catalystto form a fire retardant casting as shown in Example VI below.

Acrylic acid, when substituted for the methacrylic acid 6 used in thisexample, reacts similarly, yielding the acrylate diester ofl-pentachlorophenoxy 2,3-propanediol.

Example VI A casting of the methacrylic diester prepared in Example Vwas made by adding 71 milligrams of ditertiary butyl peroxide to 14.3grams of the molten diester. This solution was poured into a cell andoven cured for 4 /2 hours at a maximum temperature of 280 F.

The casting was found to be very flame resistant and qualified asself-extinguishing when tested according to ASTM Test Method D-63544.The casting ceased to produce a flame within 1 to 2 seconds afterremoval from a flame. This is very superior according to ASTMspecifications which consider a self-extinguishing period of 60 secondsas being indicative of a flame retardant material.

Interpolymers of described diesters may be prepared by reacting withvinyl monomers such as styrene, vinyl chloride, acrylic acid,methacrylic acid, methyl methacrylate, methyl acrylate and the like.

Although specific examples of the invention have been set forthhereinabove, it is not intended that the invention be limited solelythereto, but to include all the variations and modifications fallingwithin the scope of the appended claims.

We claim:

1. A diester of an alpha, beta, monoethylenically unsaturatedmonocarboxylic acid in which the unsaturation is present in a terminalCH C group, with a halophenoxymethyl alkanediol, in which at least oneof the hydroxy groups is a primary group, and wherein the halogen isselected from the class consisting of chlorine, bromine and fluorine andthe alkanediol group attached to the halophenoxymethyl radical containsfrom about 2 to 12 carbon atoms wherein no hydroxyl group is attached toa carbon atom which is more than three carbon atoms from the eitherlinkages.

2. The composition of matter of claim 1 wherein the halogen is chlorine.

3. The composition of matter of claim 2 wherein the monoethylenicallyunsaturated carboxylic acid is acrylic acid.

4. The composition of matter of claim 2 wherein the monoethylenicallyunsaturated carboxylic acid is methacrylic acid.

5. The acrylate diester of Z-pentachlorophenoxymethyl- 2-ethyl1,3-propanediol.

6. The methacrylate diester of 2-pentachlorophenoxymethyl-2-ethyl1,3-propanediol.

7. The acrylate diester of Z-pentachlorophenoxymethyl-2-rnethyl1,3-propanediol.

8. The methacrylate diester of 2-pentachlorophenoxymethyl-Z-methyl1,3-propanediol.

9. The methacrylic diester of l-pentachlorophenoxy 2,3-propanediol.

10. A compound of the structure wherein R is a member of the classconsisting of 7 R is a member of the class consisting of hydrogenradicals and alkyl radicals containing from 1 to 10 carbon atoms with Rbeing hydrogen When R is n -0CG=CH, R is a member of the classconsisting of halogen radicals, hydrogen radicals and alkyl radicals andAr is a mononuclear aromatic hydrocarbon containing from 1 to 5 halogensubstituents selected from the class consisting of 10 chlorine, bromineand fluorine.

11. The compound of claim 10 wherein R is R is alkyl and R is hydrogen.

8 12. An interpolymer of the diester of claim 1 with at least onepolymerizable monomer containing a CH =C group.

References Cited by the Examiner UNITED STATES PATENTS 2,755,303 7/1956Schnell 260486 3,004,073 10/1961 Wismer et a1. 260-6l3 3,056,843 10/1962Wismer 260-6l3 FOREIGN PATENTS 788,278 12/1957 Great Britain.

OTHER REFERENCES Weinman et al.: Chem Abstracts, vol. 41, 4885c (1947).

WILLIAM H. SHORT, Primary Examiner.

H. N. BURSTEIN, Examiner.

1. A DIESTER OF AN ALPHA, BETA, MONOETHYLENICALLY UNSATURATEDMONOCARBOXYLIC ACID IN WHICH THE UNSATURATION IS PRESENT IN A TERMINALCH2=C<GROUP, WITH A HALOPHENOXYMETHYL ALKANEDIOL, IN WHICH AT LEAST ONEOF THE HYDROXY GROUPS IS A PRIMARY GROUP, AND WHEREIN THE HALOGEN ISSELECTED FROM THE CLASS CONSISTING OF CHLORINE, BROMINE AND FLUORINE ANDTHE ALKANEDIOL GROUP ATTACHED TO A HALOPHENOXYMETHYL RADICAL CONTAINSFROM ABOUT 2 TO 12 CARBON ATOMS WHEREIN N HYDROXYL GROUP IS ATTACHED TOA CARBON ATOM WHICH IS MORE THAN THREE CARBON ATOMS FROM THE EITHERLINKAGES.
 12. AN INTERPOLYMER OF THE DIESTER OF CLAIM 1 WITH AT LEASTONE POLYMERIZABLE MONOMER CONTAINING A CH2=C< GROUP.